1. Technical Field
The disclosure relates to an image sensor for imaging an object to generate image data of the object. The disclosure also relates to an imaging device, an endoscope, and an endoscope system.
2. Related Art
Conventionally, an image sensor such as a complementary metal-oxide semiconductor (CMOS) image sensor is configured such that imaging signals transferred row by row are held in a sample-and-hold circuit and sequentially output to a horizontal output signal line for each pixel by a column reading circuit, whereby the imaging signals are read, and the signals are output from an output amplifier circuit. In addition, in order to prevent a deterioration in a response property when a large amount of light enters a photoelectric conversion device, such a technique is conventionally known that a clip voltage of an amplifier circuit is set by an output voltage of a reference voltage circuit (for example, refer to JP 2008-277915 A). Specifically, the reference voltage circuit includes an operational amplifier in which a current source, a plurality of resistors, and a plurality of transistors are used. Generally, the reference voltage circuit disclosed in JP 2008-277915 A is used for a reference voltage of an output amplifier circuit in an image sensor, whereby a video signal is output with a high degree of accuracy.